Seawater reverse osmosis desalination plant at community-scale: Role of an innovative pretreatment on process performances and intensification

[Display omitted] •GAC filter followed by UF guaranteed stable RO rejection rate and pressure loss.•GAC filter removed most of DOC present in seawater by adsorption or biodegradation.•RO recovery rate reached 70% with low footprint GAC+UF pretreatment.•Neither RO nor UF chemical cleanings were needed in 50days of operation. Among desalination processes, the use of seawater reverse osmosis (RO) increased in the last few years. Pretreatment before RO is an essential step to guarantee the success of the whole process. Indeed, biofouling of RO membranes usually occurs when bacteria, their potential nutrients such as dissolved organic carbon (DOC), and precursors such as transparent exopolymer particles (TEP), present in natural seawater, are not successfully removed by the pretreatments. Consequently, in this study, coupling granular activated carbon (GAC) adsorption and ultrafiltration as a pretreatment before RO is proposed on a community-scale desalination plant. This plant was designed to produce 5m3d−1 of desalinated water and was continuously operated on site with natural seawater. The two-month study of this desalination plant showed that the GAC bed could highly reduce by 20–80% DOC concentration. Ultrafiltration could retain most of TEP and bacteria before RO. RO parameters were stable meaning that no biofouling was detected. Therefore, the need of chemicals was close to zero and the RO recovery rate reached 70% enabling RO energy consumption to reach 4kWhm−3. The results showed the potential of process intensification in such desalination plants.